Description

(E)-2-Butenoyl Chloride CAS NO 625-35-4 is a high-purity, reactive acid chloride derivative of crotonic acid, serving as a critical acylating agent and versatile synthetic building block in advanced organic synthesis. Its value lies in enabling efficient carbon-chain elongation and the introduction of the (E)-configured butenoyl moiety into target molecules with high selectivity. This compound is essential for research chemists and process development scientists in the pharmaceutical, agrochemical, and specialty chemical industries who require reliable, high-quality intermediates for API synthesis and material science applications.

Application

• Pharmaceutical Intermediate: Key building block for the synthesis of active pharmaceutical ingredients (APIs), particularly those requiring an α,β-unsaturated carbonyl scaffold.
• Agrochemical Synthesis: Used in the production of herbicides, fungicides, and plant growth regulators that incorporate the crotonoyl functional group.
• Polymer Chemistry: Acts as a monomer or co-monomer in the synthesis of specialty polymers and functional materials.
• Peptide & Protein Modification: Employed as an acylating agent for selective modification of amino groups in peptides and biochemical probes.
• Organic Synthesis Reagent: A versatile reagent for Friedel-Crafts acylation, esterification, and amide bond formation under mild conditions.
• Material Science Research: Used in surface functionalization and the creation of novel organic-inorganic hybrid materials.
• Flavor & Fragrance Industry: Intermediate in the synthesis of certain unsaturated esters and lactones used in complex aroma chemicals.

Basic Information

Product Name	(E)-2-Butenoyl Chloride
CAS No.	625-35-4
Molecular Formula	C4H5ClO
Molecular Weight	104.54 g/mol
Synonyms	Crotonoyl Chloride; trans-2-Butenoyl Chloride; (E)-Crotonyl Chloride; trans-Crotonoyl Chloride; 2-Butenoyl Chloride, (E)-; But-2-enoyl chloride; 1-Oxo-2-butenyl chloride; 3-Chloro-3-buten-2-one (tautomer)
EINECS	210-887-6

Quality Control

Our (E)-2-Butenoyl Chloride is manufactured under strict quality management systems. Every batch undergoes rigorous analytical testing, including chromatography (GC/HPLC) and spectroscopic methods (IR, NMR), to ensure identity, purity, and consistency. Certificates of Analysis (COA) detailing all specifications are provided with each shipment. We support compliance with REACH, FDA (for intermediate use), and cGMP guidelines as applicable for industrial and research applications.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, well-ventilated place at temperatures between 2°C and 8°C (refrigerated) or as specified on the label. Due to its hygroscopic and moisture-sensitive nature, containers must be kept tightly sealed under an inert atmosphere (e.g., nitrogen or argon) after opening. Keep away from heat, sparks, open flames, strong bases, and oxidizing agents.

Specification

Item	Specification
Appearance	Clear, colorless to pale yellow liquid
Identification (IR)	Conforms to structure
Assay (GC)	≥ 98.0%
Purity (HPLC)	≥ 97.0%
Water Content (KF)	≤ 0.5%
Isomer Purity ((E)-isomer)	≥ 99.0%

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.